Fixes the issues with Jump, JumpRel, Call, CallRel

gpu/command_buffer/service/cmd_parser.h

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file contains the command parser class.
 
 #ifndef GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
 #define GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_
 
 #include "gpu/command_buffer/common/constants.h"
@@ skipping 14 matching lines @@
                 CommandBufferOffset start_get,
                 AsyncAPIInterface *handler);
 
   // Gets the "get" pointer. The get pointer is an index into the command
   // buffer considered as an array of CommandBufferEntry.
   CommandBufferOffset get() const { return get_; }
 
   // Sets the "get" pointer. The get pointer is an index into the command buffer
   // considered as an array of CommandBufferEntry.
   bool set_get(CommandBufferOffset get) {
-    if (get < entry_count_) {
+    if (get >= 0 && get < entry_count_) {
       get_ = get;
       return true;
     }
     return false;
   }
 
   // Sets the "put" pointer. The put pointer is an index into the command
   // buffer considered as an array of CommandBufferEntry.
   void set_put(CommandBufferOffset put) { put_ = put; }
 
@@ skipping 42 matching lines @@
       unsigned int arg_count,
       const void* cmd_data) = 0;
 
   // Returns a name for a command. Useful for logging / debuging.
   virtual const char* GetCommandName(unsigned int command_id) const = 0;
 };
 
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_SERVICE_CMD_PARSER_H_